p-channel MOSFET

The equations for the drain current of a p-channel MOSFET in cut-off, linear and saturation mode are:

Here ID is the drain current, VDS is the drain-source voltage, VGS is the gate-source voltage, VT is the threshold voltage, L is the length of the transistor, W is the width of the transistor, Cox is the specific capacitance of the gate in F/m, and μp is the mobility.

MOSFET charateristics are typically drawn for serveral gate voltages. In the figure below, the threshold voltage is -0.7 V and the gate voltages are -2, -3, -4, -5 and -6 V.

IDS [mA]
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
7

VDS [V]

W =

m

L =

m

Cox =

F/m

μp =

cm/Vs 

VT =

V

VDS,min =

V

 

Vg[1] =

V

Vg[2] =

V

Vg[3] =

V

Vg[4] =

V

Vg[5] =

V

Vg[6] =

V

Vg[7] =

V

Vg[8] =

V

Vg[9] =

V

Vg[10] =

V